HLA class I histocompatibility antigen A alpha chain (HLA-A*02:01) (HLA-A2)

The HLA class I histocompatibility antigen A alpha chain, specifically the HLA-A*02:01 allele, is a crucial component of the human major histocompatibility complex (MHC) class I system. Its primary biological function is to bind and present intracellularly derived peptides (typically 8–10 amino acids) on the cell surface for surveillance by CD8+ cytotoxic T lymphocytes (CTLs). This mechanism allows the immune system to identify and destroy cells that are expressing foreign viral proteins or mutated tumor antigens. In modern oncology, HLA-A*02:01 is a cornerstone of precision immunotherapy because it is the most common HLA allele in many populations, particularly Caucasians. Therapeutic strategies such as TCR-engineered T-cell (TCR-T) therapies and bispecific T-cell engagers (ImmTACs) are designed to target specific tumor-associated antigens (e.g., gp100, MAGE-A4, NY-ESO-1) restricted to this specific HLA molecule. For instance, the drug Tebentafusp targets the gp100 peptide specifically when presented by HLA-A*02:01. Because these therapies only work in patients carrying this allele, HLA-A*02:01 status is an essential biomarker for patient eligibility in clinical trials and approved treatments.

Other names

MHC class I antigen A*2Human leukocyte antigen A2HLA-A*02:01Major histocompatibility complex class I AHLA-A heavy chain

Peptide-MHC (pMHC) complex formation for recognition by T-cell receptors (TCRs); Target for TCR-bispecific engagers and TCR-engineered T-cell therapies (TCR-T).